About Air Circulation in Airplanes

Through the engine of an aircraft, the inside of a cabin receives ventilation through outside air every two to three minutes. In addition, each aircraft on JAL's fleet is installed with a HEPA system* to maintain the cabin`s air purity levels.

  • High - Efficiency Particulate Air (HEPA) Filter - Designed to capture at least 99.97 percent of fine airborne particles larger than at least 0.3 micrometer.

Flow of the air using HEPA filter image

  1. The aircraft receives external air through the engine
    *The Boeing 787 uses electric compressors to feed external air directly into its air-conditioning system, rather than from the engine.
  2. The air-conditioning system adjusts the compressed air to an appropriate temperature and supplies the clean air throughout the cabin.
  3. The differential pressure will push the air inside the cabin toward the belly of the aircraft and is discharged from the cabin pressure control valve.
  4. A portion of the circulated air flows back to the air-conditioning system through a HEPA filter, making the air clean and sterile.

May 14, 2020

Japan Airlines